Anyone use muriatic acid to remove surface rust? I want to clean up my lower control arms before reinstalling them and I want to get all the flaky rust. Any other options?

EVAPORUST

This picture is what my LCA's look like after soaking them out in a 5 gallon pail of Evaporust.
Looks like they were just made at the stamping plant.
Clean them up, squeaky clean with whatever solvent you prefer, then soak them out.

it works, but is nasty stuff to get rid of.
Citric acid works just as well. you can by it powdered and soak them in it instead.
While the rust part is just as nasty, the acid part is not as big of a deal.
naval jelly also works on surface rust.

The problem with Muriatic acid:
1) very strong and harmful fumes
2) it attacks the base metal
3) the items will flash rust instantly after neutralizing

There are much better products. My preferred removal method is:
step 1) blast of as much as possible
step 2) immerse or wash with a rust converter to get the rust that's in the pores. Allow this to dry, leaving the phosphate protective coating.

Try a product called Ospho. It works much better than evaporust.
These products are only intended for surface rust. Anything more and you will need to mechanically remove the rust then treat it.

Another vote for Ospho

I was introduced to Ospho by guy working on a tug boat. They use a needle gun to knock off scale and then treat with ospho before painting. He gave me two 5 gallon buckets of it and I have been hooked since.

Muric acid is good for cleaning out the water passages in your heads and block

When I would have a overheated beater id flush the cooling system with a gallon of ma with water and not leave it in long, just a couple minutes.

1/2 the time it worked. 1/2 the time it killed it off.

That was a long long time ago, id not do the same today, thats very bad stuff. Id look for other options.

I use Evaporust and it works great. The plus is you can pour the waste in the sewer drain once it stops working. Any type of waste acid here and I would have to take it to the chemical recycle building at the landfill.

I looked for naval jelly here years ago and came up empty handed.

If your control arms have major rust and pitting underneath I'd just find another pair.

They use it in swimming pools where people get it on there skin. Wear gloves if you have to put your hand in it, in other words use your brain. I've used every form of rust remover, I have vats of molasses, electrolysis tanks, muriatic acid tanks and I use osfo stuff. If you have a little or delicate part use the evoporust product $$$$. If you need fast, muriatic is the one, what you buy now is diluted but I still cut in half. Wash good when removed then spray with Crud Cutter, sold in paint stores, it will keep it from rusting back. Did my lca about three weeks ago, still no rust back, in about two months I'll paint. Remember, they all have there good points and bad points. After the muriatic been used awhile and lost its power I mix it with weed killer to get the stubborn grass out of my driveway. The ph just burns it up. I can hear the tree huggers now.

I don't know what the issues with disposal is. You dilute any acid with enough water and its harmless ... flush it down the drain !!!

Ive used phosphoric acid before. Its not as strong or quick as muratic acid, but Cleans off rust and leaves a coating to inhibit rust. Usally called prep an etch and found at many places.

More about the fumes: if you use it in a closed space like a garage, the fumes can attack everything metal in the area, if the exposure time is several hours or more.

After I left my shop for the day, a quart or two of vinegar leaked on the floor and put surface rust on every piece of steel in the room by morning. And this was just vinegar, not nearly as strong as typical store-bought dilute muratic acid.

Yes, Evapo-Rust isn't cheap, but all things considered, it's very popular for a reason.

I need more coffee this morning but i seem to foggily remember that Muriatic acid (HCL) can cause "hydrogen embrittlement" cracking even long after it has been used.

HBC can cause a steel part to fail far below its yield strength,
even below its fatique strength. Roughly this can mean breaking at 20% of the load you would expect.

It has other safety problems:

https://simple.m.wikipedia.org/wiki/Hydrochloric_acid

Osphro and Naval Jelly have been around for a long time and used by the US Navy

http://cameo.mfa.org/wiki/Naval_Jelly_Rust_Dissolver

There are links in my previous posts on rust removal on Evaporust about cheap extenders like vinegar of expensive rust removers.

I bought a gallon of Safest Rust Remover 4:1 concentrate but have not experimented with it yet.

My brother favors using a pneumatic needle scaler
followed by Osphro
or a rust converter.
The needle scaler handled right can add a "shot peened" strengthening effect to steel parts.

Don't weaken a steel part's strength while "pretty-ing it up."

I use Ospho.

http://ospho.com/

A little bit of side info:

All acids attack/remove rust AND the base metal to different degrees. Stronger = faster, but not really "better". In order of "acid strength", sulfuric acid (battery acid is about 15% sulfuric), hydrochloric (muriatic is 12% hyrochloric acid) > phosphoric acid > citric acid. I've never used ospho, but based on it's name it's an ortho-phosphoric acid based product (phosphoric acid).

All of these acids can be "neutralized" with baking soda making them OK to go down the drain in most places. fyi- it's good to have some baking soda around to neutralize any acid you get on your skin or on on concrete/other metal.

I've always used some type of phoshporic acid based product. Sulfuric is WAY too strong & hydrocholic (even 12% muriatic) is too strong too in my opinion, but yo might get away with it if you watch the parts VERY closely. If you aren't in a big hurry, you "might" be able to find some oxalic acid. I used to use that years ago to restore beer cans since it would SLOWLY remove the rust & leave the paint/ink on the cans alone for the most part.

This is why I sold my '72 SSP I was going to clone into a '71 RR. After sandblasting the entire front clip (not fenders), over several days with a Harbor Freight sand blaster, I left an open, empty gallon container of muriatic acid in the garage over night one night. Next morning I came out and every piece of metal in my garage was flash rusted. I was so disgusted, I sold the car.

Before:



After...



I did start blasting again, but then stopped in disgust and sold the damn thing.

Quitter !!

The metals dissolved in acid are easily diluted by adding lots of water. Remember, they're dissolved. Just like sugar dissolves in water.

They are going into a sewer system that handles millions of gallons per day. Enough said.

I came across the little jugs of Evaporust at my local Walmart, marked down for clearance. For small jobs they are probably adequate. You may check your local store.

R.

I saw Evaporust one gallon jugs in a Tractor Supply yesterday for $20,
which was cheaper than the $26 per gallon at Harbor Freight.

Amazon has some suppliers selling Evaporust in 5 gallon containers with a dipping basket for reasonable prices.

Now that i know that Evaporust will only "chelate" a limited amount of rust,
my revised strategy is to dip a non-delicate rusty part first in cheap white distilled Vinegar,
rinse,
then finish in Evaporust.

I saw Evaporust one gallon jugs in a Tractor Supply yesterday for $20,
which was cheaper than the $26 per gallon at Harbor Freight.

Amazon has some suppliers selling Evaporust in 3 gallon containers with a dipping basket for reasonable prices.

https://www.amazon.com/Evapo-rust-Gallon...PTF7SKW9DRZX2MC

Now that i know that Evaporust will only "chelate" a limited amount of rust,
my revised strategy is to dip a non-delicate rusty part first in cheap white distilled Vinegar,
rinse,
then finish in Evaporust.

This has been my method for a few years now. Vinegar is MUCH cheaper than Evapo, and works almost as fast.

Evapo-Rust is $16 per gallon if you order 5 gallons from Northern Tool & Equipment and pick it up at the store with no freight charge.

I just had the 3.5 gallon bucket w/strainer delivered from Summit for $60.
Really looking forward to seeing how this stuff works

How often can evaporust be reused?

Depends on how much you use it, and put thru the pail.
When it won't "derust" anymore, and when it turns black, you will then know.

I got very little use out of it, seemed like a one shot deal, open to the air kills it the fastest imo resealible container might help

Oh ya, never heard that about Evaporust before.

Yea, even covered it didn't last long, depends on your wallet size.

My understanding on Evaporust is that it keeps eating on any rust particles in the solution even when put back into a sealed container, even when sealed from air. Also heard that straining or filtering the big and little chunks out of the liquid helps it last longer when not in use. Can't prove any of this by me as it's only hearsay on my part. I am still using that cheep old grocery store vinegar on things I need to de-rust.

another vinegar user here too

http://www.evapo-rust.com/product-info/faqs/

Acids "eat at" iron oxide on the surface of a part and send the oxygen off into the liquid in one direction, and the iron in another.

( scientificly: the acid helps the iron and oxygen ions dissociate from the metal surface)

Strong acids can do this with iron atoms alone. Strong acids continue to "eat" iron atoms off the metal surface, turn them into ions, and these ions wander off into the liquid. All the metal could eventually disappear this way. The original part would disappear eventually.

Evaporust is different.
It "buddies up" to the rust molecule at the metal surface and carries the still combined iron and oxygen atoms away together into the liquid.

This process has a special name: Chelation.

The special difference is that once Chelation has got the iron oxide rust off the metal surface it does not continue and remove pure iron. The original part will not disappear.

The above descriptions are simplifications. Please do not report me to the Chemistry departments that might have me tarred and feathered.

From the FAQ

One gallon of EVAPO- RUST® will remove the rust from 300 pounds of moderately rusted steel. If any of the bath evaporates, simply replace it with fresh tap water.